// Copyright (c) 2019-2024 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.
module c

import v.ast
import v.token
import v.util

fn (mut g Gen) safe_shift_fn_name(left_type ast.Type, op token.Kind) string {
    shift_type := g.table.unalias_num_type(g.unwrap_generic(left_type))
    prefix := if op == .left_shift { 'v__lshift_' } else { 'v__rshift_' }
    return prefix + util.no_dots(g.base_type(shift_type))
}

fn (mut g Gen) gen_safe_shift_expr(node ast.InfixExpr) {
    left_type := match node.left {
        ast.CastExpr {
            node.left.typ
        }
        else {
            g.type_resolver.get_type_or_default(node.left, node.left_type)
        }
    }

    g.write(g.safe_shift_fn_name(left_type, node.op))
    g.write('(')
    g.expr(node.left)
    g.write(', (u64)')
    g.expr(node.right)
    g.write(')')
}

fn (mut g Gen) infix_expr(node ast.InfixExpr) {
    g.expected_fixed_arr = true
    defer {
        g.expected_fixed_arr = false
    }
    if node.auto_locked != '' {
        g.writeln('sync__RwMutex_lock(&${node.auto_locked}->mtx);')
    }
    match node.op {
        .arrow {
            g.infix_expr_arrow_op(node)
        }
        .eq, .ne {
            g.infix_expr_eq_op(node)
        }
        .gt, .ge, .lt, .le {
            g.infix_expr_cmp_op(node)
        }
        .key_in, .not_in {
            g.infix_expr_in_op(node)
        }
        .key_is, .not_is {
            g.infix_expr_is_op(node)
        }
        .plus, .minus, .mul, .power, .div, .mod {
            g.infix_expr_arithmetic_op(node)
        }
        .left_shift {
            // `a << b` can mean many things in V ...
            // TODO: disambiguate everything in the checker; cgen should not decide all this.
            // Instead it should be as simple, as the branch for .right_shift is.
            // `array << val` should have its own separate operation internally.
            g.infix_expr_left_shift_op(node)
        }
        .right_shift {
            g.gen_safe_shift_expr(node)
        }
        .and, .logical_or {
            g.infix_expr_and_or_op(node)
        }
        else {
            // `x & y == 0` => `(x & y) == 0` in C
            need_par := node.op in [.amp, .pipe, .xor]
            if need_par {
                g.write('(')
            }
            g.gen_plain_infix_expr(node)
            if need_par {
                g.write(')')
            }
        }
    }

    if node.auto_locked != '' {
        g.writeln(';')
        g.write('sync__RwMutex_unlock(&${node.auto_locked}->mtx)')
    }
}

// infix_expr_arrow_op generates C code for pushing into channels (chan <- val)
fn (mut g Gen) infix_expr_arrow_op(node ast.InfixExpr) {
    mut resolved_left_type := g.resolved_expr_type(node.left, node.left_type)
    if resolved_left_type == 0 {
        resolved_left_type = node.left_type
    }
    resolved_left_type = g.unwrap_generic(g.recheck_concrete_type(resolved_left_type))
    mut left := g.unwrap(resolved_left_type)
    if left.sym.info !is ast.Chan {
        left = g.unwrap(node.left_type)
    }
    g.note_chan_type_definition(left.typ)
    styp := g.styp(left.typ)
    elem_type := g.unwrap_generic(g.recheck_concrete_type((left.sym.info as ast.Chan).elem_type))
    gen_or := node.or_block.kind != .absent
    tmp_opt := if gen_or { g.new_tmp_var() } else { '' }
    if gen_or {
        elem_styp := g.styp(elem_type)
        g.register_chan_push_option_fn(elem_styp, styp)
        g.write('${option_name}_void ${tmp_opt} = __Option_${styp}_pushval(')
    } else {
        g.write('__${styp}_pushval(')
    }
    g.expr(node.left)
    g.write(', ')
    if g.table.sym(elem_type).kind in [.sum_type, .interface] {
        g.expr_with_cast(node.right, node.right_type, elem_type)
    } else {
        g.expr(node.right)
    }
    g.write(')')
    if gen_or {
        g.or_block(tmp_opt, node.or_block, ast.void_type)
    }
}

// infix_expr_eq_op generates code for `==` and `!=`
fn (mut g Gen) infix_expr_eq_op(node ast.InfixExpr) {
    mut left_type := g.type_resolver.get_type_or_default(node.left, node.left_type)
    mut right_type := g.type_resolver.get_type_or_default(node.right, node.right_type)
    if (g.cur_fn != unsafe { nil } && g.cur_concrete_types.len > 0)
        || left_type.has_flag(.generic) || right_type.has_flag(.generic)
        || g.type_has_unresolved_generic_parts(left_type)
        || g.type_has_unresolved_generic_parts(right_type) {
        resolved_left := g.resolved_expr_type(node.left, node.left_type)
        if resolved_left != 0 {
            // Don't override a smartcasted concrete type (from the checker)
            // with a sumtype/option-sumtype from resolved_expr_type, which
            // doesn't check scope smartcasts.
            resolved_sym := g.table.sym(resolved_left)
            left_sym := g.table.sym(left_type)
            is_sumtype_override := resolved_sym.kind in [.sum_type, .interface]
                && left_sym.kind !in [.sum_type, .interface]
            is_option_introduction := resolved_left.has_flag(.option)
                && !left_type.has_flag(.option)
            // Don't strip option flag when comparing with none — the scope
            // may have an unwrapped smartcast from a fallthrough guard, but
            // the none check itself needs the option type.
            is_option_removal_for_none := left_type.has_flag(.option)
                && !resolved_left.has_flag(.option) && node.right is ast.None
            if !is_sumtype_override && !is_option_introduction && !is_option_removal_for_none {
                left_type = resolved_left
            }
        }
        resolved_right := g.resolved_expr_type(node.right, node.right_type)
        if resolved_right != 0 {
            resolved_sym := g.table.sym(resolved_right)
            right_sym := g.table.sym(right_type)
            is_sumtype_override := resolved_sym.kind in [.sum_type, .interface]
                && right_sym.kind !in [.sum_type, .interface]
            is_option_introduction := resolved_right.has_flag(.option)
                && !right_type.has_flag(.option)
            if !is_sumtype_override && !is_option_introduction {
                right_type = resolved_right
            }
        }
    }
    // Promote literal element types in arrays (e.g. []int_literal -> []int)
    // so that equality comparisons match the correct array type.
    left_type = g.promote_literal_array_type(left_type)
    right_type = g.promote_literal_array_type(right_type)
    left := g.unwrap(left_type)
    right := g.unwrap(right_type)
    mut has_defined_eq_operator := false
    mut eq_operator_expects_ptr := false
    if m := g.table.find_method(left.sym, '==') {
        // For != on generic struct types, check if the == operator was defined on
        // a generic parent (receiver type has generic flag or is a different type).
        // In that case, use _struct_eq for != (full structural comparison) instead
        // of negating the user-defined ==, matching master's behavior.
        mut skip_for_generic_ne := false
        if node.op == .ne && m.receiver_type.has_flag(.generic) {
            skip_for_generic_ne = true
        }
        if !skip_for_generic_ne {
            has_defined_eq_operator = true
            eq_operator_expects_ptr = m.receiver_type.is_ptr()
        }
    }
    // TODO: investigate why the following is needed for vlib/v/tests/string_alias_test.v and vlib/v/tests/anon_fn_with_alias_args_test.v
    has_alias_eq_op_overload := left.sym.info is ast.Alias && left.sym.has_method('==')
    if g.pref.translated && !g.is_builtin_mod {
        g.gen_plain_infix_expr(node)
        return
    }
    left_sym := g.table.sym(left_type)
    right_sym := g.table.sym(right_type)
    left_is_option := left_type.has_flag(.option) || (left_sym.kind == .alias
        && left_sym.info is ast.Alias && left_sym.info.parent_type.has_flag(.option))
    right_is_option := right_type.has_flag(.option) || (right_sym.kind == .alias
        && right_sym.info is ast.Alias && right_sym.info.parent_type.has_flag(.option))
    is_none_check := left_is_option && node.right is ast.None
    if is_none_check {
        g.gen_is_none_check(node)
    } else if (left.typ.is_ptr() && right.typ.is_int())
        || (right.typ.is_ptr() && left.typ.is_int())
        || (left.typ.is_ptr() && right.typ == ast.nil_type) {
        g.gen_plain_infix_expr(node)
    } else if (left.typ.idx() == ast.string_type_idx || (!has_defined_eq_operator
        && left.unaliased.idx() == ast.string_type_idx)) && node.right is ast.StringLiteral
        && (node.right.val == '' || (node.left is ast.SelectorExpr
        || (node.left is ast.Ident && node.left.or_expr.kind == .absent
        && !(node.left.obj is ast.Var && node.left.obj.ct_type_var == .smartcast
        && g.table.sym(g.unwrap_generic(node.left.obj.orig_type)).kind == .sum_type)))) {
        if node.right.val == '' {
            // `str == ''` -> `str.len == 0` optimization
            g.write('(')
            g.expr(ast.Expr(node.left))
            g.write(')')
            arrow := if left.typ.is_ptr() { '->' } else { '.' }
            g.write('${arrow}len ${node.op} 0')
        } else if node.left is ast.Ident {
            // vmemcmp(left, "str", sizeof("str")) optimization
            slit := cescape_nonascii(util.smart_quote(node.right.val, node.right.is_raw))
            var := g.expr_string(ast.Expr(node.left))
            arrow := if left.typ.is_ptr() { '->' } else { '.' }
            if node.op == .eq {
                g.write('_SLIT_EQ(${var}${arrow}str, ${var}${arrow}len, "${slit}")')
            } else {
                g.write('_SLIT_NE(${var}${arrow}str, ${var}${arrow}len, "${slit}")')
            }
        } else {
            // fast_string_eq optimization for string selector comparison to literals
            if node.op == .ne {
                g.write('!builtin__fast_string_eq(')
            } else {
                g.write('builtin__fast_string_eq(')
            }
            g.expr(node.left)
            g.write(', ')
            g.expr(ast.Expr(node.right))
            g.write(')')
        }
    } else if has_defined_eq_operator {
        if node.op == .ne {
            g.write('!')
        }
        if left.sym.kind == .struct && (left.sym.info as ast.Struct).generic_types.len > 0 {
            concrete_types := (left.sym.info as ast.Struct).concrete_types
            mut method_name := '${left.sym.cname}__eq'
            if left.unaliased_sym.is_builtin() {
                method_name = 'builtin__${method_name}'
            }
            method_name = g.generic_fn_name(concrete_types, method_name)
            g.write(method_name)
        } else {
            mut method_name := if has_alias_eq_op_overload {
                g.styp(left.typ.set_nr_muls(0))
            } else {
                g.styp(left.unaliased.set_nr_muls(0))
            }
            mut is_builtin_or_alias_to_builtin := left.sym.is_builtin()
            if !has_alias_eq_op_overload && !is_builtin_or_alias_to_builtin
                && left.sym.info is ast.Alias {
                alias_info := left.sym.info as ast.Alias
                parent_sym := g.table.sym(alias_info.parent_type)
                is_builtin_or_alias_to_builtin = parent_sym.is_builtin()
            }
            if is_builtin_or_alias_to_builtin {
                method_name = 'builtin__${method_name}'
            }
            g.write(method_name)
            g.write('__eq')
        }
        g.write('(')
        g.write('*'.repeat(left.typ.nr_muls()))
        if eq_operator_expects_ptr {
            g.write('&')
        }
        if node.left is ast.ArrayInit && g.table.sym(node.left_type).kind == .array_fixed {
            g.fixed_array_init_with_cast(node.left, node.left_type)
        } else {
            g.expr(ast.Expr(node.left))
        }
        g.write2(', ', '*'.repeat(right.typ.nr_muls()))
        if eq_operator_expects_ptr {
            g.write('&')
        }
        if node.right is ast.ArrayInit && g.table.sym(node.right_type).kind == .array_fixed {
            g.fixed_array_init_with_cast(node.right, node.right_type)
        } else {
            g.expr(node.right)
        }
        g.write(')')
    } else if (left.unaliased.idx() == right.unaliased.idx()
        && left.sym.kind in [.array, .array_fixed, .alias, .map, .struct, .sum_type, .interface])
        || (left.unaliased_sym.kind == .array_fixed && right.unaliased_sym.kind == .array_fixed) {
        if g.pref.translated && !g.is_builtin_mod {
            g.gen_plain_infix_expr(node)
            return
        }
        kind := if left.sym.kind == .alias && right.sym.kind != .alias {
            left.unaliased_sym.kind
        } else {
            left.sym.kind
        }
        match kind {
            .alias {
                // optimize simple eq/ne operation on numbers
                if left.unaliased_sym.is_int() {
                    if left.typ.is_ptr() && node.left.is_auto_deref_var() && !right.typ.is_pointer() {
                        g.write('*'.repeat(left.typ.nr_muls()))
                    }
                    g.expr(node.left)
                    g.write(' ${node.op} ')
                    if right.typ.is_ptr() {
                        g.write('*'.repeat(right.typ.nr_muls()))
                    }
                    g.expr(node.right)
                    g.no_eq_method_types[left.typ] = true
                } else {
                    ptr_typ := g.equality_fn(left.typ)
                    if node.op == .ne {
                        g.write('!')
                    }
                    g.write('${ptr_typ}_alias_eq(')
                    if left.typ.is_ptr() {
                        g.write('*'.repeat(left.typ.nr_muls()))
                    }
                    if node.left is ast.StructInit && left.unaliased_sym.is_primitive_fixed_array() {
                        s := g.styp(left.unaliased)
                        g.write('(${s})')
                    }
                    g.expr(node.left)
                    g.write(', ')
                    if node.right is ast.StructInit
                        && right.unaliased_sym.is_primitive_fixed_array() {
                        s := g.styp(right.unaliased)
                        g.write('(${s})')
                    }
                    if right.typ.is_ptr() {
                        g.write('*'.repeat(right.typ.nr_muls()))
                    }
                    g.expr(node.right)
                    g.write(')')
                }
            }
            .array {
                ptr_typ := g.equality_fn(left.unaliased.clear_flag(.shared_f))
                if node.op == .ne {
                    g.write('!')
                }
                g.write('${ptr_typ}_arr_eq(')
                if left.typ.is_ptr() && !left.typ.has_flag(.shared_f) {
                    if node.left !is ast.ArrayInit {
                        g.write('*'.repeat(left.typ.nr_muls()))
                    }
                }
                g.expr(ast.Expr(node.left))
                if left.typ.has_flag(.shared_f) {
                    g.write('->val')
                }
                g.write(', ')
                if right.typ.is_ptr() && !right.typ.has_flag(.shared_f) {
                    if node.right !is ast.ArrayInit {
                        g.write('*'.repeat(right.typ.nr_muls()))
                    }
                }
                g.expr(ast.Expr(node.right))
                if right.typ.has_flag(.shared_f) {
                    g.write('->val')
                }
                g.write(')')
            }
            .array_fixed {
                ptr_typ := g.equality_fn(left.unaliased)
                if node.op == .ne {
                    g.write('!')
                }
                g.write('${ptr_typ}_arr_eq(')
                if left.typ.is_ptr() {
                    g.write('*')
                }
                if node.left is ast.ArrayInit {
                    if !node.left.has_index {
                        s := g.styp(left.unaliased)
                        g.write('(${s})')
                    }
                } else if node.left is ast.StructInit
                    && left.unaliased_sym.is_primitive_fixed_array() {
                    s := g.styp(left.unaliased)
                    g.write('(${s})')
                }
                g.expr(node.left)
                g.write(', ')
                if node.right is ast.ArrayInit {
                    if !node.right.has_index {
                        s := g.styp(right.unaliased)
                        g.write('(${s})')
                    }
                } else if node.right is ast.StructInit
                    && right.unaliased_sym.is_primitive_fixed_array() {
                    s := g.styp(right.unaliased)
                    g.write('(${s})')
                }
                g.expr(ast.Expr(node.right))
                g.write(')')
            }
            .map {
                ptr_typ := g.equality_fn(left.unaliased)
                if node.op == .ne {
                    g.write('!')
                }
                g.write('${ptr_typ}_map_eq(')
                if left.typ.is_ptr() {
                    g.write('*'.repeat(left.typ.nr_muls()))
                }
                g.expr(ast.Expr(node.left))
                g.write(', ')
                if right.typ.is_ptr() {
                    g.write('*'.repeat(right.typ.nr_muls()))
                }
                g.expr(ast.Expr(node.right))
                g.write(')')
            }
            .struct {
                if left_is_option && right_is_option {
                    bare_typ := g.equality_fn(left.unaliased.clear_flag(.option).set_nr_muls(0))
                    old_inside_opt_or_res := g.inside_opt_or_res
                    g.inside_opt_or_res = true
                    inside_and_rhs := g.infix_left_var_name.len > 0
                    mut lv := ''
                    mut rv := ''
                    if inside_and_rhs {
                        lv = g.expr_string(node.left)
                        rv = g.expr_string(node.right)
                    } else {
                        left_tmp := g.expr_to_ctemp_before_stmt(node.left, left_type)
                        right_tmp := g.expr_to_ctemp_before_stmt(node.right, right_type)
                        lv = left_tmp.name
                        rv = right_tmp.name
                    }
                    if node.op == .eq {
                        g.write('(')
                    } else {
                        g.write('!(')
                    }
                    g.write('(${lv}.state == 2 && ${rv}.state == 2) || ')
                    g.write('(${lv}.state == ${rv}.state && ${lv}.state != 2 && ')
                    if left.typ.is_ptr() {
                        ptr_styp := g.styp(left.unaliased.clear_flag(.option))
                        nr_muls := left.typ.nr_muls()
                        deref := '*'.repeat(nr_muls)
                        lp := '*(${ptr_styp}*)&${lv}.data'
                        rp := '*(${ptr_styp}*)&${rv}.data'
                        g.write('(${lp} == ${rp} || (${lp} != 0 && ${rp} != 0 && ')
                        g.write('${bare_typ}_struct_eq(${deref}${lp}, ${deref}${rp})')
                        g.write('))')
                    } else {
                        styp := g.base_type(left_type)
                        g.write('${bare_typ}_struct_eq(*(${styp}*)&${lv}.data, *(${styp}*)&${rv}.data)')
                    }
                    g.write('))')
                    g.inside_opt_or_res = old_inside_opt_or_res
                } else {
                    ptr_typ := g.equality_fn(left.unaliased)
                    if left.typ.is_ptr() || right.typ.is_ptr() {
                        left_is_addr_of_lvalue := node.left is ast.PrefixExpr
                            && node.left.op == .amp && node.left.right.is_lvalue()
                        right_is_addr_of_lvalue := node.right is ast.PrefixExpr
                            && node.right.op == .amp && node.right.right.is_lvalue()
                        if left.typ.is_ptr() && right.typ.is_ptr()
                            && (left_is_addr_of_lvalue || right_is_addr_of_lvalue) {
                            g.gen_plain_infix_expr(node)
                        } else {
                            g.gen_struct_pointer_eq_op(node, left_type, right_type, ptr_typ)
                        }
                    } else {
                        if node.op == .ne {
                            g.write('!')
                        }
                        g.write('${ptr_typ}_struct_eq(')
                        g.expr(node.left)
                        g.write(', ')
                        g.expr(node.right)
                        g.write(')')
                    }
                }
            }
            .sum_type {
                ptr_typ := g.equality_fn(left.unaliased)
                if node.op == .ne {
                    g.write('!')
                }
                tmp_left_is_opt := g.left_is_opt
                g.left_is_opt = true
                g.write('${ptr_typ}_sumtype_eq(')
                if left.typ.is_ptr() {
                    g.write('*'.repeat(left.typ.nr_muls()))
                }
                g.expr(ast.Expr(node.left))
                g.write(', ')
                if right.typ.is_ptr() {
                    g.write('*'.repeat(right.typ.nr_muls()))
                }
                g.expr(node.right)
                g.write(')')
                g.left_is_opt = tmp_left_is_opt
            }
            .interface {
                ptr_typ := g.equality_fn(left.unaliased)
                if node.op == .ne {
                    g.write('!')
                }
                g.write('${ptr_typ}_interface_eq(')
                if left.typ.is_ptr() {
                    g.write('*'.repeat(left.typ.nr_muls()))
                }
                g.expr(node.left)
                g.write(', ')
                if right.typ.is_ptr() {
                    g.write('*'.repeat(right.typ.nr_muls()))
                }
                g.expr(node.right)
                g.write(')')
            }
            else {
                g.gen_plain_infix_expr(node)
            }
        }
    } else if left.unaliased.idx() in [ast.u32_type_idx, ast.u64_type_idx]
        && right.unaliased.is_signed() {
        g.gen_safe_integer_infix_expr(
            op:            node.op
            unsigned_type: left.unaliased
            unsigned_expr: node.left
            signed_type:   right.unaliased
            signed_expr:   node.right
        )
    } else if right.unaliased.idx() in [ast.u32_type_idx, ast.u64_type_idx]
        && left.unaliased.is_signed() {
        g.gen_safe_integer_infix_expr(
            op:            node.op
            reverse:       true
            unsigned_type: right.unaliased
            unsigned_expr: node.right
            signed_type:   left.unaliased
            signed_expr:   node.left
        )
    } else if left_is_option && right_is_option {
        old_inside_opt_or_res := g.inside_opt_or_res
        g.inside_opt_or_res = true
        if node.op == .eq {
            g.write('(')
        } else {
            g.write('!(')
        }
        g.write('(')
        g.expr(node.left)
        g.write('.state == 2 && ')
        g.expr(node.right)
        g.write('.state == 2) || (')
        g.expr(node.left)
        g.write('.state == ')
        g.expr(node.right)
        g.write('.state && ')
        g.expr(node.left)
        g.write('.state != 2 && !memcmp(&')
        g.expr(node.left)
        g.write('.data, &')
        g.expr(node.right)
        g.write('.data, sizeof(${g.base_type(left_type)}))))')
        g.inside_opt_or_res = old_inside_opt_or_res
    } else {
        g.gen_plain_infix_expr(node)
    }
}

fn (mut g Gen) gen_struct_pointer_eq_op(node ast.InfixExpr, left_type ast.Type, right_type ast.Type, ptr_typ string) {
    // When inside a short-circuit `&&` condition (infix_left_var_name is set),
    // do not hoist temp vars before the containing statement, as that would
    // evaluate expressions (e.g. as-casts from smartcasts) before the
    // short-circuit check has run. Instead, use inline expressions.
    inside_and_rhs := g.infix_left_var_name.len > 0
    mut stmt_str := ''
    mut restore_stmt := false
    mut left_expr := ''
    mut right_expr := ''
    if left_type.is_ptr() && !node.left.is_lvalue() && !inside_and_rhs {
        if !restore_stmt {
            stmt_str = g.go_before_last_stmt().trim_space()
            g.empty_line = true
            restore_stmt = true
        }
        mut left_tmp := g.new_ctemp_var(node.left, left_type)
        g.gen_ctemp_var(mut left_tmp)
        left_expr = left_tmp.name
    } else {
        left_expr = g.expr_string(node.left)
    }
    if right_type.is_ptr() && !node.right.is_lvalue() && !inside_and_rhs {
        if !restore_stmt {
            stmt_str = g.go_before_last_stmt().trim_space()
            g.empty_line = true
            restore_stmt = true
        }
        mut right_tmp := g.new_ctemp_var(node.right, right_type)
        g.gen_ctemp_var(mut right_tmp)
        right_expr = right_tmp.name
    } else {
        right_expr = g.expr_string(node.right)
    }
    if restore_stmt {
        g.write(stmt_str)
    }
    if node.op == .ne {
        g.write('!')
    }
    g.write('(')
    if left_type.is_ptr() && right_type.is_ptr() {
        g.write('${left_expr} == ${right_expr} || (${left_expr} != 0 && ${right_expr} != 0 && ')
        g.write('${ptr_typ}_struct_eq(')
        g.write('*'.repeat(left_type.nr_muls()))
        g.write(left_expr)
        g.write(', ')
        g.write('*'.repeat(right_type.nr_muls()))
        g.write(right_expr)
        g.write('))')
    } else if left_type.is_ptr() {
        g.write('${left_expr} != 0 && ${ptr_typ}_struct_eq(')
        g.write('*'.repeat(left_type.nr_muls()))
        g.write(left_expr)
        g.write(', ${right_expr})')
    } else {
        g.write('${right_expr} != 0 && ${ptr_typ}_struct_eq(${left_expr}, ')
        g.write('*'.repeat(right_type.nr_muls()))
        g.write('${right_expr})')
    }
    g.write(')')
}

// infix_expr_cmp_op generates code for `<`, `<=`, `>`, `>=`
// It handles operator overloading when necessary
fn (mut g Gen) infix_expr_cmp_op(node ast.InfixExpr) {
    mut left_type := g.resolved_expr_type(node.left, node.left_type)
    if left_type == 0 {
        left_type = node.left_type
    }
    left_type = g.unwrap_generic(g.recheck_concrete_type(left_type))
    mut right_type := g.resolved_expr_type(node.right, node.right_type)
    if right_type == 0 {
        right_type = node.right_type
    }
    right_type = g.unwrap_generic(g.recheck_concrete_type(right_type))
    left := g.unwrap(left_type)
    right := g.unwrap(right_type)

    mut has_operator_overloading := false
    mut operator_expects_ptr := false
    mut operator_method := ast.Fn{}
    if m := g.table.find_method(left.sym, '<') {
        has_operator_overloading = true
        operator_expects_ptr = m.receiver_type.is_ptr()
        operator_method = m
    } else if m := left.sym.find_method_with_generic_parent('<') {
        has_operator_overloading = true
        operator_expects_ptr = m.receiver_type.is_ptr()
        operator_method = m
    }

    if g.pref.translated && !g.is_builtin_mod {
        g.gen_plain_infix_expr(node)
        return
    }
    if left.sym.kind == .struct && (left.sym.info as ast.Struct).generic_types.len > 0 {
        if node.op in [.le, .ge] {
            g.write('!')
        }
        concrete_types := (left.sym.info as ast.Struct).concrete_types
        mut method_name := '${left.sym.cname}__lt'
        if left.unaliased_sym.is_builtin() {
            method_name = 'builtin__${method_name}'
        }
        specialized_suffix := g.generic_fn_name(concrete_types, '')
        if specialized_suffix != '' && !method_name.ends_with(specialized_suffix) {
            method_name = g.generic_fn_name(concrete_types, method_name)
        }
        method_name = g.specialized_method_name_from_receiver(operator_method, left.typ,
            method_name)
        g.write(method_name)
        if node.op in [.lt, .ge] {
            g.write2('(', '*'.repeat(left.typ.nr_muls()))
            if operator_expects_ptr {
                g.write('&')
            }
            g.expr(ast.Expr(node.left))
            g.write2(', ', '*'.repeat(right.typ.nr_muls()))
            if operator_expects_ptr {
                g.write('&')
            }
            g.expr(node.right)
            g.write(')')
        } else {
            g.write2('(', '*'.repeat(right.typ.nr_muls()))
            if operator_expects_ptr {
                g.write('&')
            }
            g.expr(node.right)
            g.write2(', ', '*'.repeat(left.typ.nr_muls()))
            if operator_expects_ptr {
                g.write('&')
            }
            g.expr(node.left)
            g.write(')')
        }
    } else if left.unaliased_sym.kind == right.unaliased_sym.kind && has_operator_overloading {
        if node.op in [.le, .ge] {
            g.write('!')
        }
        mut method_name := '${g.styp(left.typ.set_nr_muls(0))}__lt'
        if left.unaliased_sym.is_builtin() {
            method_name = 'builtin__${method_name}'
        }
        method_name = g.specialized_method_name_from_receiver(operator_method, left.typ,
            method_name)
        g.write(method_name)
        if node.op in [.lt, .ge] {
            g.write2('(', '*'.repeat(left.typ.nr_muls()))
            if operator_expects_ptr {
                g.write('&')
            }
            if node.left is ast.ArrayInit && g.table.sym(node.left_type).kind == .array_fixed {
                g.fixed_array_init_with_cast(node.left, left_type)
            } else {
                g.expr(node.left)
            }
            g.write2(', ', '*'.repeat(right.typ.nr_muls()))
            if operator_expects_ptr {
                g.write('&')
            }
            if node.right is ast.ArrayInit && g.table.sym(node.right_type).kind == .array_fixed {
                g.fixed_array_init_with_cast(node.right, right_type)
            } else {
                g.expr(node.right)
            }
            g.write(')')
        } else {
            g.write2('(', '*'.repeat(right.typ.nr_muls()))
            if operator_expects_ptr {
                g.write('&')
            }
            g.expr(node.right)
            g.write2(', ', '*'.repeat(left.typ.nr_muls()))
            if operator_expects_ptr {
                g.write('&')
            }
            g.expr(node.left)
            g.write(')')
        }
    } else if left.unaliased.idx() in [ast.u32_type_idx, ast.u64_type_idx]
        && right.unaliased.is_signed() {
        g.gen_safe_integer_infix_expr(
            op:            node.op
            unsigned_type: left.unaliased
            unsigned_expr: node.left
            signed_type:   right.unaliased
            signed_expr:   node.right
        )
    } else if right.unaliased.idx() in [ast.u32_type_idx, ast.u64_type_idx]
        && left.unaliased.is_signed() {
        g.gen_safe_integer_infix_expr(
            op:            node.op
            reverse:       true
            unsigned_type: right.unaliased
            unsigned_expr: node.right
            signed_type:   left.unaliased
            signed_expr:   node.left
        )
    } else {
        g.gen_plain_infix_expr(node)
    }
}

fn (mut g Gen) infix_expr_in_sumtype_interface_array(infix_exprs []ast.InfixExpr) {
    for i in 0 .. infix_exprs.len {
        g.infix_expr_is_op(infix_exprs[i])
        if i != infix_exprs.len - 1 {
            g.write(' || ')
        }
    }
}

// infix_expr_in_op generates code for `in` and `!in`
fn (mut g Gen) infix_expr_in_op(node ast.InfixExpr) {
    mut left_type := node.left_type
    mut right_type := node.right_type
    // In generic contexts, AST-stored types may be stale from a previous instantiation.
    if g.cur_fn != unsafe { nil } && g.cur_concrete_types.len > 0 {
        resolved_left := g.resolved_expr_type(node.left, node.left_type)
        if resolved_left != 0 {
            resolved_sym := g.table.sym(resolved_left)
            left_sym := g.table.sym(left_type)
            if resolved_sym.kind !in [.sum_type, .interface]
                || left_sym.kind in [.sum_type, .interface] {
                left_type = resolved_left
            }
        }
        resolved_right := g.resolved_expr_type(node.right, node.right_type)
        if resolved_right != 0 {
            resolved_sym := g.table.sym(resolved_right)
            right_sym := g.table.sym(right_type)
            if resolved_sym.kind !in [.sum_type, .interface]
                || right_sym.kind in [.sum_type, .interface] {
                right_type = resolved_right
            }
        }
    }
    left := g.unwrap(left_type)
    right := g.unwrap(right_type)
    if node.op == .not_in {
        g.write('!')
    }
    if right.unaliased_sym.kind == .array {
        if left.sym.kind in [.sum_type, .interface] {
            if node.right is ast.ArrayInit {
                if node.right.exprs.len > 0
                    && g.table.sym(node.right.expr_types[0]).kind !in [.sum_type, .interface] {
                    mut infix_exprs := []ast.InfixExpr{}
                    for i in 0 .. node.right.exprs.len {
                        infix_exprs << ast.InfixExpr{
                            op:         .key_is
                            left:       node.left
                            left_type:  node.left_type
                            right:      node.right.exprs[i]
                            right_type: node.right.expr_types[i]
                        }
                    }
                    g.write('(')
                    g.infix_expr_in_sumtype_interface_array(infix_exprs)
                    g.write(')')
                    return
                }
            }
        }
        if node.right is ast.ArrayInit {
            elem_type := node.right.elem_type
            elem_sym := g.table.sym(elem_type)
            // TODO: replace ast.Ident check with proper side effect analysis
            if node.right.exprs.len > 0 && (node.left is ast.Ident
                || node.left is ast.IndexExpr || node.left is ast.SelectorExpr) {
                // `a in [1,2,3]` optimization => `a == 1 || a == 2 || a == 3`
                // avoids an allocation
                g.write('(')
                if elem_sym.kind == .sum_type && left.sym.kind != .sum_type {
                    if node.left_type in elem_sym.sumtype_info().variants {
                        new_node_left := ast.CastExpr{
                            arg:       ast.empty_expr
                            typ:       elem_type
                            expr:      node.left
                            expr_type: node.left_type
                        }
                        g.infix_expr_in_optimization(new_node_left, node.left_type, node.right)
                    }
                } else {
                    g.infix_expr_in_optimization(node.left, node.left_type, node.right)
                }
                g.write(')')
                return
            }
        }
        if right.sym.info is ast.Array {
            elem_type := right.sym.info.elem_type
            elem_type_ := g.unwrap(elem_type)
            if elem_type_.sym.kind == .sum_type {
                if ast.mktyp(node.left_type) in elem_type_.sym.sumtype_info().variants {
                    new_node_left := ast.CastExpr{
                        arg:       ast.empty_expr
                        typ:       elem_type
                        expr:      node.left
                        expr_type: ast.mktyp(node.left_type)
                    }
                    g.write('(')
                    g.gen_array_contains(node.right_type, node.right, elem_type, new_node_left)
                    g.write(')')
                    return
                }
            } else if elem_type_.sym.kind == .interface {
                new_node_left := ast.CastExpr{
                    arg:       ast.empty_expr
                    typ:       elem_type
                    expr:      node.left
                    expr_type: ast.mktyp(node.left_type)
                }
                g.write('(')
                g.gen_array_contains(node.right_type, node.right, elem_type, new_node_left)
                g.write(')')
                return
            }
        }
        g.write('(')
        g.gen_array_contains(right_type, node.right, left_type, node.left)
        g.write(')')
    } else if right.unaliased_sym.kind == .map {
        g.write('_IN_MAP(')
        if !left.typ.is_ptr() {
            mut sym_map := g.table.sym(right_type)
            if sym_map.info is ast.Alias {
                sym_map = g.table.sym((sym_map.info as ast.Alias).parent_type)
            }
            styp := g.styp(if sym_map.info is ast.Map {
                (sym_map.info as ast.Map).key_type
            } else {
                node.left_type
            })
            if g.table.final_sym(node.left_type).kind == .array_fixed && node.left is ast.Ident {
                g.expr(node.left)
            } else {
                g.write('ADDR(${styp}, ')
                g.expr(node.left)
                g.write(')')
            }
        } else {
            g.expr(node.left)
        }
        g.write(', ')
        if !right.typ.is_ptr() || right.typ.has_flag(.shared_f) {
            g.write('ADDR(map, ')
            g.expr(node.right)
            if right.typ.has_flag(.shared_f) {
                g.write('->val')
            }
            g.write(')')
        } else {
            g.expr(node.right)
        }
        g.write(')')
    } else if right.unaliased_sym.kind == .array_fixed {
        if left.sym.kind in [.sum_type, .interface] {
            if node.right is ast.ArrayInit {
                if node.right.exprs.len > 0 {
                    mut infix_exprs := []ast.InfixExpr{}
                    for i in 0 .. node.right.exprs.len {
                        infix_exprs << ast.InfixExpr{
                            op:         .key_is
                            left:       node.left
                            left_type:  node.left_type
                            right:      node.right.exprs[i]
                            right_type: node.right.expr_types[i]
                        }
                    }
                    g.write('(')
                    g.infix_expr_in_sumtype_interface_array(infix_exprs)
                    g.write(')')
                    return
                }
            }
        }
        if node.right is ast.ArrayInit {
            if node.right.exprs.len > 0 {
                // `a in [1,2,3]!` optimization => `a == 1 || a == 2 || a == 3`
                // avoids an allocation
                g.write('(')
                g.infix_expr_in_optimization(node.left, node.left_type, node.right)
                g.write(')')
                return
            }
        }
        if right.sym.info is ast.ArrayFixed {
            elem_type := right.sym.info.elem_type
            elem_type_ := g.unwrap(elem_type)
            if elem_type_.sym.kind == .sum_type {
                if ast.mktyp(node.left_type) in elem_type_.sym.sumtype_info().variants {
                    new_node_left := ast.CastExpr{
                        arg:       ast.empty_expr
                        typ:       elem_type
                        expr:      node.left
                        expr_type: ast.mktyp(node.left_type)
                    }
                    g.write('(')
                    g.gen_array_contains(node.right_type, node.right, elem_type, new_node_left)
                    g.write(')')
                    return
                }
            }
        }
        g.write('(')
        g.gen_array_contains(right_type, node.right, left_type, node.left)
        g.write(')')
    } else if right.unaliased_sym.kind == .string && node.right !is ast.RangeExpr {
        g.write2('(', 'string_contains(')
        g.expr(node.right)
        g.write(', ')
        g.expr(node.left)
        g.write('))')
    } else if node.right is ast.RangeExpr {
        // call() in min..max
        if node.left is ast.CallExpr {
            line := g.go_before_last_stmt().trim_space()
            g.empty_line = true
            tmp_var := g.new_tmp_var()
            g.write('${g.styp(node.left.return_type)} ${tmp_var} = ')
            g.expr(ast.Expr(node.left))
            g.writeln(';')
            g.write(line)
            g.write('(')
            g.write('${tmp_var} >= ')
            g.expr(node.right.low)
            g.write(' && ')
            g.write('${tmp_var} < ')
            g.expr(node.right.high)
            g.write(')')
        } else {
            g.write('(')
            g.expr(node.left)
            g.write(' >= ')
            g.expr(node.right.low)
            g.write(' && ')
            g.expr(node.left)
            g.write(' < ')
            g.expr(node.right.high)
            g.write(')')
        }
    }
}

// infix_expr_in_optimization optimizes `<var> in <array>` expressions,
// and transform them in a series of equality comparison
// i.e. `a in [1,2,3]` => `a == 1 || a == 2 || a == 3`
fn (mut g Gen) infix_expr_in_optimization(left ast.Expr, left_type ast.Type, right ast.ArrayInit) {
    tmp_var := if left is ast.CallExpr { g.new_tmp_var() } else { '' }
    mut elem_sym := g.table.sym(right.elem_type)
    left_parent_idx := g.table.sym(left_type).parent_idx
    for i, array_expr in right.exprs {
        match elem_sym.kind {
            .string, .alias, .sum_type, .map, .interface, .array, .struct {
                if elem_sym.kind == .string {
                    is_auto_deref_var := left.is_auto_deref_var()
                    if left is ast.Ident && left.or_expr.kind == .absent
                        && array_expr is ast.StringLiteral {
                        var := g.expr_string(left)
                        slit :=
                            cescape_nonascii(util.smart_quote(array_expr.val, array_expr.is_raw))
                        mut needs_deref := false
                        if left.info is ast.IdentVar && left.obj is ast.Var {
                            if g.table.sym(left.obj.typ).kind in [.interface, .sum_type] {
                                needs_deref = left.obj.smartcasts.len == 0
                            }
                        }
                        if is_auto_deref_var || needs_deref {
                            g.write('_SLIT_EQ(${var}->str, ${var}->len, "${slit}")')
                        } else {
                            g.write('_SLIT_EQ(${var}.str, ${var}.len, "${slit}")')
                        }
                        if i < right.exprs.len - 1 {
                            g.write(' || ')
                        }
                        continue
                    } else if array_expr is ast.StringLiteral {
                        g.write('builtin__fast_string_eq(')
                    } else {
                        g.write('builtin__string__eq(')
                    }
                    if is_auto_deref_var || (left is ast.Ident && left.info is ast.IdentVar
                        && g.table.sym(left.obj.typ).kind in [.interface, .sum_type]) {
                        g.write('*')
                    }
                } else {
                    ptr_typ := g.equality_fn(right.elem_type)
                    if elem_sym.kind == .alias {
                        // optimization for alias to number
                        if elem_sym.is_int() {
                            g.expr(left)
                            g.write(' == ')
                            if left_parent_idx != 0 && !((array_expr is ast.SelectorExpr
                                && array_expr.typ == left_type)
                                || (array_expr is ast.Ident && array_expr.obj.typ == left_type)) {
                                g.write('(${g.styp(left_parent_idx)})')
                            }
                            g.expr(array_expr)
                            if i < right.exprs.len - 1 {
                                g.write(' || ')
                            }
                            continue
                        } else {
                            g.write('${ptr_typ}_alias_eq(')
                        }
                    } else if elem_sym.kind == .sum_type {
                        g.write('${ptr_typ}_sumtype_eq(')
                    } else if elem_sym.kind == .map {
                        g.write('${ptr_typ}_map_eq(')
                    } else if elem_sym.kind == .interface {
                        g.write('${ptr_typ}_interface_eq(')
                    } else if elem_sym.kind == .array {
                        g.write('${ptr_typ}_arr_eq(')
                    } else if elem_sym.kind == .struct {
                        g.write('${ptr_typ}_struct_eq(')
                    }
                }
                if left is ast.CallExpr {
                    if i == 0 {
                        line := g.go_before_last_stmt().trim_space()
                        g.empty_line = true
                        g.write('${g.styp(left.return_type)} ${tmp_var} = ')
                        g.expr(left)
                        g.writeln(';')
                        g.write2(line, tmp_var)
                    } else {
                        g.write(tmp_var)
                    }
                } else {
                    g.expr(left)
                }
                g.write(', ')
                g.expr(array_expr)
                g.write(')')
            }
            else { // works in function kind
                if left is ast.CallExpr {
                    if i == 0 {
                        line := g.go_before_last_stmt().trim_space()
                        g.empty_line = true
                        g.write('${g.styp(left.return_type)} ${tmp_var} = ')
                        g.expr(left)
                        g.writeln(';')
                        g.write2(line, tmp_var)
                    } else {
                        g.write(tmp_var)
                    }
                } else {
                    g.expr(left)
                }
                g.write(' == ')
                if elem_sym.kind == .array_fixed {
                    g.write('(${g.styp(right.elem_type)})')
                }
                g.expr(array_expr)
            }
        }

        if i < right.exprs.len - 1 {
            g.write(' || ')
        }
    }
}

fn (mut g Gen) type_tag_expr_for_is_left(node ast.InfixExpr, is_aggregate bool, is_orig_sumtype bool) string {
    mut left_expr := ''
    if is_aggregate {
        left_expr = '${node.left}'
    } else {
        if is_orig_sumtype {
            g.prevent_sum_type_unwrapping_once = true
        }
        left_expr = g.expr_string(node.left)
    }
    left_value_expr := if node.left_type.nr_muls() > 1 {
        '(${'*'.repeat(node.left_type.nr_muls() - 1)}${left_expr})'
    } else {
        '(${left_expr})'
    }
    dot_or_ptr := if node.left_type.is_ptr() { '->' } else { '.' }
    return '${left_value_expr}${dot_or_ptr}_typ'
}

fn (mut g Gen) write_type_tag_expr_for_is_left(node ast.InfixExpr, is_aggregate bool, is_orig_sumtype bool) {
    g.write('(')
    if node.left_type.nr_muls() > 1 {
        g.write('*'.repeat(node.left_type.nr_muls() - 1))
    }
    if is_aggregate {
        g.write('${node.left}')
    } else if is_orig_sumtype {
        g.prevent_sum_type_unwrapping_once = true
        g.expr(node.left)
    } else {
        g.expr(node.left)
    }
    g.write(')')
    if node.left_type.is_ptr() {
        g.write('->')
    } else {
        g.write('.')
    }
    g.write('_typ')
}

fn (mut g Gen) write_is_type_tag_condition(node ast.InfixExpr, is_aggregate bool, is_orig_sumtype bool, cmp_op string, index_exprs []string) {
    if index_exprs.len == 0 {
        g.write(if cmp_op == '==' { 'false' } else { 'true' })
        return
    }
    if index_exprs.len == 1 {
        g.write_type_tag_expr_for_is_left(node, is_aggregate, is_orig_sumtype)
        g.write(' ${cmp_op} ${index_exprs[0]}')
        return
    }
    if is_aggregate {
        tag_expr := g.type_tag_expr_for_is_left(node, is_aggregate, is_orig_sumtype)
        g.write_type_tag_condition(tag_expr, cmp_op, index_exprs)
        return
    }
    tag_tmp := g.new_tmp_var()
    if !g.is_cc_msvc {
        g.write('({ ${ast.int_type_name} ${tag_tmp} = ')
        g.write_type_tag_expr_for_is_left(node, is_aggregate, is_orig_sumtype)
        g.write('; ')
        g.write_type_tag_condition(tag_tmp, cmp_op, index_exprs)
        g.write('; })')
        return
    }
    mut cur_line := if g.inside_ternary > 0 {
        g.go_before_ternary().trim_space()
    } else {
        g.go_before_last_stmt().trim_space()
    }
    if g.inside_return && cur_line.ends_with('return') {
        cur_line += ' '
    }
    g.empty_line = true
    g.write('${ast.int_type_name} ${tag_tmp} = ')
    g.write_type_tag_expr_for_is_left(node, is_aggregate, is_orig_sumtype)
    g.writeln(';')
    g.write(cur_line)
    g.write_type_tag_condition(tag_tmp, cmp_op, index_exprs)
}

// infix_expr_is_op generates code for `is` and `!is`
fn (mut g Gen) infix_expr_is_op(node ast.InfixExpr) {
    mut left_sym := g.table.final_sym(g.unwrap_generic(g.type_resolver.get_type_or_default(node.left,
        node.left_type)))
    is_aggregate := node.left is ast.Ident && g.comptime.get_ct_type_var(node.left) == .aggregate
    mut right_type := g.unwrap_generic(g.recheck_concrete_type(node.right_type))
    if right_type.is_ptr() && g.table.final_sym(right_type.deref()).kind == .interface {
        right_type = right_type.deref()
    }
    right_sym := g.table.final_sym(right_type)
    // When the LHS is a smartcast variable whose original type is a sum type,
    // use the original sum type so the `is` check works on the tag field.
    // But only when the smartcast target is NOT itself a sum type — for nested
    // sum types (e.g., Outer→Inner→MyStruct), normal smartcast unwrapping
    // must proceed to generate the correct inner dereference.
    mut is_orig_sumtype := false
    if node.left is ast.Ident && node.left.obj is ast.Var {
        v := node.left.obj as ast.Var
        if v.smartcasts.len > 0 && v.is_mut && v.orig_type != 0 {
            orig_sym := g.table.final_sym(v.orig_type)
            smartcast_target_sym := g.table.final_sym(v.smartcasts.last())
            if orig_sym.kind == .sum_type && smartcast_target_sym.kind != .sum_type {
                left_sym = unsafe { orig_sym }
                is_orig_sumtype = true
            }
        }
    }
    if (left_sym.kind == .sum_type || is_aggregate) && node.left_type.nr_muls() > 0
        && right_type.nr_muls() <= node.left_type.nr_muls() {
        right_type = right_type.set_nr_muls(0)
    }
    if left_sym.kind == .interface && right_sym.kind == .interface {
        g.gen_interface_is_op(node)
        return
    }

    cmp_op := if node.op == .key_is { '==' } else { '!=' }
    if left_sym.kind == .interface {
        sub_type := match node.right {
            ast.TypeNode {
                right_type
            }
            ast.None {
                ast.idx_to_type(g.table.type_idxs['None__'])
            }
            else {
                ast.no_type
            }
        }

        g.write_is_type_tag_condition(node, is_aggregate, is_orig_sumtype, cmp_op, g.matching_interface_variant_index_exprs(left_sym,
            sub_type))
        return
    } else if left_sym.kind == .sum_type || is_aggregate {
        mut aggregate_parent_type := node.left_type
        if is_aggregate {
            aggregate_sym := g.table.sym(node.left_type)
            if aggregate_sym.info is ast.Aggregate {
                aggregate_parent_type = aggregate_sym.info.sum_type
            }
        }
        sumtype_parent_type := if is_orig_sumtype && node.left is ast.Ident
            && node.left.obj is ast.Var {
            (node.left.obj as ast.Var).orig_type
        } else if is_aggregate {
            aggregate_parent_type
        } else {
            node.left_type
        }
        if node.right is ast.None {
            g.write_is_type_tag_condition(node, is_aggregate, is_orig_sumtype, cmp_op, [
                '${ast.none_type.idx()}',
            ])
        } else if node.right is ast.Ident && node.right.name == g.comptime.comptime_for_variant_var {
            mut variant_idx := g.type_resolver.get_ct_type_or_default('${g.comptime.comptime_for_variant_var}.typ',
                ast.void_type)
            if (left_sym.kind == .sum_type || is_aggregate) && node.left_type.nr_muls() > 0
                && variant_idx.nr_muls() <= node.left_type.nr_muls() {
                variant_idx = variant_idx.set_nr_muls(0)
            }
            g.write_is_type_tag_condition(node, is_aggregate, is_orig_sumtype, cmp_op, g.matching_sumtype_variant_type_idx_exprs(sumtype_parent_type,
                variant_idx))
        } else if node.right is ast.TypeNode {
            g.write_is_type_tag_condition(node, is_aggregate, is_orig_sumtype, cmp_op, g.matching_sumtype_variant_type_idx_exprs(sumtype_parent_type,
                right_type))
        } else {
            g.write_type_tag_expr_for_is_left(node, is_aggregate, is_orig_sumtype)
            g.write(' ${cmp_op} ')
            g.expr(node.right)
        }
        return
    }
    if node.right is ast.None {
        g.write_type_tag_expr_for_is_left(node, is_aggregate, is_orig_sumtype)
        g.write(' ${cmp_op} ')
        g.write('${ast.none_type.idx()}')
    } else if node.right is ast.Ident && node.right.name == g.comptime.comptime_for_variant_var {
        variant_idx := g.type_resolver.get_ct_type_or_default('${g.comptime.comptime_for_variant_var}.typ',
            ast.void_type)
        g.write_type_tag_expr_for_is_left(node, is_aggregate, is_orig_sumtype)
        g.write(' ${cmp_op} ')
        if (left_sym.kind == .sum_type || is_aggregate) && node.left_type.nr_muls() > 0
            && variant_idx.nr_muls() <= node.left_type.nr_muls() {
            g.write('${int(variant_idx.set_nr_muls(0))}')
        } else {
            g.write('${int(variant_idx)}')
        }
    } else if node.right is ast.TypeNode {
        g.write_type_tag_expr_for_is_left(node, is_aggregate, is_orig_sumtype)
        g.write(' ${cmp_op} ')
        g.write('${int(right_type)}')
    } else {
        g.write_type_tag_expr_for_is_left(node, is_aggregate, is_orig_sumtype)
        g.write(' ${cmp_op} ')
        g.expr(node.right)
    }
}

fn (mut g Gen) gen_interface_is_op(node ast.InfixExpr) {
    mut left_type := g.unwrap_generic(g.recheck_concrete_type(node.left_type))
    mut right_type := g.unwrap_generic(g.recheck_concrete_type(node.right_type))
    if left_type.is_ptr() && g.table.final_sym(left_type.deref()).kind == .interface {
        left_type = left_type.deref()
    }
    if right_type.is_ptr() && g.table.final_sym(right_type.deref()).kind == .interface {
        right_type = right_type.deref()
    }
    mut left_sym := g.table.final_sym(left_type)
    right_sym := g.table.final_sym(right_type)

    mut info := left_sym.info as ast.Interface
    right_info := right_sym.info as ast.Interface
    left_variants := info.implementor_types(true)
    right_variants := right_info.implementor_types(true)
    lock info.conversions {
        common_variants := info.conversions[right_type] or {
            c := g.interface_conversion_variants(left_variants, right_variants)
            info.conversions[right_type] = c
            c
        }
        left_sym.info = info
        if common_variants.len == 0 {
            g.write('false')
            return
        }
    }
    g.write('I_${left_sym.cname}_is_I_${right_sym.cname}(')
    if node.left_type.is_ptr() {
        g.write('*')
    }
    g.expr(node.left)
    g.write(')')
}

// infix_expr_arithmetic_op generates code for `+`, `-`, `*`, `/`, and `%`
// It handles operator overloading when necessary
fn (mut g Gen) is_string_type(typ ast.Type) bool {
    return g.unwrap(typ).unaliased_sym.kind == .string
}

fn (mut g Gen) is_char_or_rune_string_concat_type(typ ast.Type) bool {
    return g.table.unaliased_type(g.unwrap_generic(typ)).clear_flags() in [ast.char_type, ast.rune_type]
}

fn (mut g Gen) is_string_concat_type(typ ast.Type) bool {
    return g.is_string_type(typ) || g.is_char_or_rune_string_concat_type(typ)
}

fn (mut g Gen) is_string_concat_infix(node ast.InfixExpr) bool {
    if node.op != .plus {
        return false
    }
    left_type := g.type_resolver.get_type_or_default(node.left, node.left_type)
    right_type := g.type_resolver.get_type_or_default(node.right, node.right_type)
    return g.is_string_concat_type(left_type) && g.is_string_concat_type(right_type)
        && (g.is_string_type(left_type) || g.is_string_type(right_type))
}

fn (mut g Gen) collect_string_concat_parts(expr ast.Expr, mut parts []ast.Expr) {
    match expr {
        ast.InfixExpr {
            if g.is_string_concat_infix(expr) {
                g.collect_string_concat_parts(expr.left, mut parts)
                g.collect_string_concat_parts(expr.right, mut parts)
                return
            }
        }
        ast.ParExpr {
            g.collect_string_concat_parts(expr.expr, mut parts)
            return
        }
        else {}
    }

    parts << expr
}

fn (mut g Gen) gen_string_concat_many(node ast.InfixExpr) bool {
    if !g.is_string_concat_infix(node) {
        return false
    }
    mut parts := []ast.Expr{}
    g.collect_string_concat_parts(ast.Expr(node), mut parts)
    mut needs_plus_many := parts.len >= 3
    for part in parts {
        part_type := g.type_resolver.get_type_or_default(part, part.type())
        if !g.is_string_type(part_type) {
            needs_plus_many = true
            break
        }
    }
    if !needs_plus_many {
        return false
    }
    g.write('builtin__string_plus_many(${parts.len}, _MOV((string[${parts.len}]){')
    for i, part in parts {
        part_type := g.type_resolver.get_type_or_default(part, part.type())
        g.expr_with_cast(part, part_type, ast.string_type)
        if i < parts.len - 1 {
            g.write(', ')
        }
    }
    g.write('}))')
    return true
}

fn (mut g Gen) infix_expr_arithmetic_op(node ast.InfixExpr) {
    if g.gen_string_concat_many(node) {
        return
    }
    left_type := g.resolved_expr_type(node.left, node.left_type)
    right_type := g.resolved_expr_type(node.right, node.right_type)
    $if trace_ci_fixes ? {
        left_str := g.table.type_to_str(left_type)
        right_str := g.table.type_to_str(right_type)
        if left_str.contains('MyStruct') || left_str.contains('MyAlias')
            || right_str.contains('MyStruct') || right_str.contains('MyAlias') {
            eprintln('cgen infix sum left=${g.table.type_to_str(left_type)} right=${g.table.type_to_str(right_type)} node_left=${g.table.type_to_str(node.left_type)} node_right=${g.table.type_to_str(node.right_type)} cur=${g.cur_concrete_types.map(g.table.type_to_str(it))}')
        }
    }
    left := g.unwrap(left_type)
    right := g.unwrap(right_type)
    if left.sym.info is ast.Struct && left.sym.info.generic_types.len > 0 {
        mut method_name := left.sym.cname + '_' + util.replace_op(node.op.str())
        mut concrete_types := left.sym.info.concrete_types.clone()
        resolved_left_sym := g.table.final_sym(left.typ)
        if resolved_left_sym.info is ast.Struct && resolved_left_sym.info.concrete_types.len > 0 {
            concrete_types = resolved_left_sym.info.concrete_types.clone()
        }
        specialized_suffix := g.generic_fn_name(concrete_types, '')
        if specialized_suffix != '' && !method_name.ends_with(specialized_suffix) {
            method_name = g.generic_fn_name(concrete_types, method_name)
        }
        if left.sym.is_builtin() {
            method_name = 'builtin__${method_name}'
        }
        g.write2(method_name, '(')
        g.expr(node.left)
        g.write(', ')
        g.expr(node.right)
        g.write(')')
    } else {
        mut method := ast.Fn{}
        mut method_name := ''
        if left.sym.has_method(node.op.str()) {
            method = left.sym.find_method(node.op.str()) or { ast.Fn{} }
            method_name = left.sym.cname + '_' + util.replace_op(node.op.str())
            if left.sym.is_builtin() {
                method_name = 'builtin__${method_name}'
            }
        } else if left.unaliased_sym.has_method_with_generic_parent(node.op.str()) {
            method = left.unaliased_sym.find_method_with_generic_parent(node.op.str()) or {
                ast.Fn{}
            }
            method_name = left.unaliased_sym.cname + '_' + util.replace_op(node.op.str())
            if left.unaliased_sym.is_builtin() {
                method_name = 'builtin__${method_name}'
            }
            if left.unaliased_sym.info is ast.Struct
                && left.unaliased_sym.info.generic_types.len > 0 {
                mut concrete_types := left.unaliased_sym.info.concrete_types.clone()
                resolved_left_sym := g.table.final_sym(left.typ)
                if resolved_left_sym.info is ast.Struct
                    && resolved_left_sym.info.concrete_types.len > 0 {
                    concrete_types = resolved_left_sym.info.concrete_types.clone()
                }
                method_name = g.generic_fn_name(concrete_types, method_name)
            }
        } else {
            g.gen_plain_infix_expr(node)
            return
        }

        mut right_var := ''
        if node.right is ast.Ident && node.right.or_expr.kind != .absent {
            cur_line := g.go_before_last_stmt().trim_space()
            right_var = g.new_tmp_var()
            unwrapped_right_typ := right.typ.clear_option_and_result()
            g.write('${g.styp(unwrapped_right_typ)} ${right_var} = ')
            g.op_arg(ast.Expr(node.right), method.params[1].typ, unwrapped_right_typ)
            g.writeln(';')
            g.write(cur_line)
        }
        g.write2(method_name, '(')
        g.op_arg(node.left, method.params[0].typ, left.typ)
        if right_var != '' {
            g.write(', ${right_var}')
        } else {
            g.write(', ')
            g.op_arg(node.right, method.params[1].typ, right.typ)
        }
        g.write(')')

        if left.typ != 0 && !left.typ.has_option_or_result()
            && g.table.final_sym(left.typ).kind == .array_fixed {
            // it's non-option fixed array, requires accessing .ret_arr member to get the array
            g.write('.ret_arr')
        }
    }
}

// infix_expr_left_shift_op generates code for the `<<` operator
// This can either be a value pushed into an array or a bit shift
fn (mut g Gen) infix_expr_left_shift_op(node ast.InfixExpr) {
    mut left_type := if node.left is ast.ComptimeSelector {
        g.type_resolver.get_type(ast.Expr(node.left))
    } else {
        g.recheck_concrete_type(node.left_type)
    }
    resolved_left_type := g.resolved_expr_type(node.left, node.left_type)
    if resolved_left_type != 0 {
        left_type = g.unwrap_generic(g.recheck_concrete_type(resolved_left_type))
    } else if left_type == 0 || left_type.has_flag(.generic)
        || g.type_has_unresolved_generic_parts(left_type) {
        left_type = g.resolved_expr_type(node.left, node.left_type)
    }
    if left_type == 0 {
        left_type = node.left_type
    }
    mut right_type := if node.right is ast.ComptimeSelector {
        g.type_resolver.get_type(ast.Expr(node.right))
    } else {
        node.right_type
    }
    resolved_node_right_type := g.resolved_expr_type(node.right, node.right_type)
    if resolved_node_right_type != 0 {
        right_type = g.unwrap_generic(g.recheck_concrete_type(resolved_node_right_type))
    } else if right_type == 0 || right_type.has_flag(.generic)
        || g.type_has_unresolved_generic_parts(right_type) {
        right_type = g.resolved_expr_type(node.right, node.right_type)
    }
    if right_type == 0 {
        right_type = node.right_type
    }
    left := g.unwrap(left_type)
    right := g.unwrap(right_type)
    if left.unaliased_sym.kind == .array {
        // arr << val
        tmp_var := g.new_tmp_var()
        mut resolved_left := left
        concrete_left_type := g.recheck_concrete_type(left.typ)
        if concrete_left_type != 0 {
            resolved_left = g.unwrap(concrete_left_type)
        }
        if node.left is ast.Ident {
            scope_left_type := g.resolved_scope_var_type(node.left)
            if scope_left_type != 0 {
                resolved_left = g.unwrap(scope_left_type)
            }
        }
        array_info := if resolved_left.unaliased_sym.kind == .array {
            resolved_left.unaliased_sym.info as ast.Array
        } else {
            left.unaliased_sym.info as ast.Array
        }
        mut elem_type := g.unwrap_generic(g.recheck_concrete_type(array_info.elem_type))
        if elem_type == 0 || elem_type.has_flag(.generic)
            || g.type_has_unresolved_generic_parts(elem_type) {
            resolved_elem_type :=
                g.recheck_concrete_type(g.table.value_type(g.unwrap_generic(resolved_left.typ)))
            if resolved_elem_type != 0 {
                elem_type = g.unwrap_generic(resolved_elem_type)
            }
        }
        if elem_type == 0 {
            elem_type = array_info.elem_type
        }
        if node.left is ast.Ident {
            ident_elem_type := g.resolved_ident_array_elem_type(node.left)
            if ident_elem_type != 0 {
                elem_type = ident_elem_type
            }
        }
        if elem_type == ast.usize_type {
            name_elem_type := g.resolved_array_elem_type_from_name(resolved_left.sym.name)
            if name_elem_type != 0 {
                elem_type = name_elem_type
            }
        }
        if elem_type == ast.usize_type {
            call_elem_type := g.resolved_call_like_expr_type(node.right)
            if call_elem_type != 0
                && call_elem_type !in [ast.int_literal_type, ast.float_literal_type]
                && g.table.final_sym(call_elem_type).kind !in [.array, .map] {
                elem_type = call_elem_type
            }
        }
        if elem_type == ast.usize_type {
            mut candidate_elem_type := g.unwrap_generic(g.recheck_concrete_type(g.resolved_expr_type(node.right,
                node.right_type)))
            if candidate_elem_type == 0 {
                candidate_elem_type = g.unwrap_generic(g.recheck_concrete_type(node.right_type))
            }
            if candidate_elem_type != 0 && candidate_elem_type != ast.void_type
                && candidate_elem_type !in [ast.int_literal_type, ast.float_literal_type]
                && g.table.final_sym(candidate_elem_type).kind !in [.array, .map] {
                elem_type = candidate_elem_type
            }
        }
        mut elem_sym := g.table.final_sym(elem_type)
        if node.right is ast.StructInit && elem_sym.kind !in [.interface, .sum_type] {
            resolved_right_type := g.unwrap_generic(g.recheck_concrete_type(g.resolved_expr_type(ast.Expr(node.right),
                right.typ)))
            if resolved_right_type != 0
                && g.table.final_sym(resolved_right_type).kind == elem_sym.kind
                && g.table.type_to_str(resolved_right_type) == g.table.type_to_str(elem_type) {
                elem_type = resolved_right_type
                elem_sym = g.table.final_sym(elem_type)
            }
        }
        noscan := g.check_noscan(elem_type)
        elem_is_option := elem_type.has_flag(.option)
        mut prevent_push_many := g.table.sumtype_has_variant(elem_type, right_type, false)
        mut resolved_right_type := g.unwrap_generic(g.recheck_concrete_type(right_type))
        if resolved_right_type == 0 {
            resolved_right_type = g.unwrap_generic(right_type)
        }
        needs_explicit_deref := node.right is ast.Ident && resolved_right_type.is_ptr()
            && !elem_type.is_ptr() && !elem_type.is_pointer()
        rhs_is_any_value := elem_sym.kind == .any
        mut rhs_is_interface_value := elem_sym.kind == .interface
            && g.table.does_type_implement_interface(resolved_right_type, elem_type)
        if rhs_is_interface_value {
            // Don't prevent push_many when the right side is an array with matching
            // element type (e.g. []Foo << []Foo where Foo is an interface).
            resolved_right_sym := g.table.final_sym(resolved_right_type)
            if resolved_right_sym.kind == .array {
                right_elem := (resolved_right_sym.info as ast.Array).elem_type
                if right_elem == elem_type {
                    rhs_is_interface_value = false
                }
            }
        }
        if rhs_is_any_value || rhs_is_interface_value {
            prevent_push_many = true
        }
        if prevent_push_many && node.right is ast.CallExpr && !rhs_is_any_value
            && !rhs_is_interface_value {
            // Allow concatenation for array-returning calls; avoids nesting for common builder APIs.
            prevent_push_many = false
        }
        if (right.unaliased_sym.kind == .array
            || (right.unaliased_sym.kind == .struct && right.unaliased_sym.name == 'array'))
            && resolved_left.sym.nr_dims() == right.sym.nr_dims() && elem_type != right.typ
            && !elem_is_option && !prevent_push_many {
            // push an array => PUSH_MANY, but not if pushing an array to 2d array (`[][]int << []int`)
            g.write('_PUSH_MANY${noscan}(')
            // The push macro needs the plain array type (not option/result),
            // since it declares a temp var of that type.
            mut expected_push_many_atype := resolved_left.typ.clear_option_and_result()
            is_shared := expected_push_many_atype.has_flag(.shared_f)
            if !expected_push_many_atype.is_ptr() {
                // fn f(mut a []int) { a << [1,2,3] } -> type of `a` is `array_int*` -> no need for &
                g.write('&')
            } else {
                expected_push_many_atype = expected_push_many_atype.deref()
            }
            if is_shared {
                g.write('&')
            }
            if is_shared {
                expected_push_many_atype = expected_push_many_atype.clear_flag(.shared_f)
            }
            expected_push_many_sym := g.table.final_sym(g.unwrap_generic(expected_push_many_atype))
            if expected_push_many_sym.kind == .array {
                mut push_many_elem_type :=
                    g.unwrap_generic(g.recheck_concrete_type(expected_push_many_sym.array_info().elem_type))
                if push_many_elem_type == ast.int_literal_type {
                    push_many_elem_type = ast.int_type
                } else if push_many_elem_type == ast.float_literal_type {
                    push_many_elem_type = ast.f64_type
                }
                if push_many_elem_type != expected_push_many_sym.array_info().elem_type {
                    expected_push_many_atype =
                        ast.idx_to_type(g.table.find_or_register_array(push_many_elem_type))
                }
            }
            old_inside_left_shift := g.inside_left_shift
            g.inside_left_shift = true
            g.expr(node.left)
            g.inside_left_shift = old_inside_left_shift
            if node.left_type.has_flag(.shared_f) {
                g.write('->val')
            }
            if left.typ.is_ptr() && right.typ.is_ptr() {
                g.write(', *(')
            } else {
                g.write(', (')
            }
            g.expr_with_cast(node.right, right.typ, resolved_left.unaliased.clear_flag(.shared_f))
            styp := g.styp(expected_push_many_atype)
            g.write('), ${tmp_var}, ${styp})')
        } else {
            // push a single element
            elem_type_str := g.styp(elem_type)
            elem_is_array_var := !elem_is_option && elem_sym.kind in [.array, .array_fixed]
                && node.right is ast.Ident
            g.write('builtin__array_push${noscan}((array*)')
            mut needs_addr := false
            if !left.typ.is_ptr()
                || (node.left_type.has_flag(.shared_f) && !node.left_type.deref().is_ptr()) {
                if node.left is ast.CallExpr {
                    g.write('ADDR(${g.styp(node.left_type)}, ')
                    needs_addr = true
                } else {
                    g.write('&')
                }
            }
            old_inside_left_shift := g.inside_left_shift
            g.inside_left_shift = true
            g.expr(node.left)
            g.inside_left_shift = old_inside_left_shift
            if node.left_type.has_flag(.shared_f) {
                g.write('->val')
            }
            if needs_addr {
                g.write(')')
            }
            if elem_sym.kind == .function {
                g.write(', _MOV((voidptr[]){ ')
            } else if elem_is_array_var {
                addr := if elem_sym.kind == .array_fixed { '' } else { '&' }
                g.write(', ${addr}')
            } else {
                g.write(', _MOV((${elem_type_str}[]){ ')
            }
            if elem_type.has_flag(.option) {
                g.expr_with_opt(node.right, right.typ, elem_type)
            } else {
                // if g.autofree
                needs_clone := !g.is_builtin_mod && elem_type.idx() == ast.string_type_idx
                    && elem_type.nr_muls() == 0
                    && node.right !in [ast.StringLiteral, ast.StringInterLiteral, ast.CallExpr, ast.IndexExpr, ast.InfixExpr]
                if needs_clone {
                    g.write('builtin__string_clone(')
                }
                if node.right is ast.CastExpr && node.right.expr is ast.ArrayInit
                    && elem_sym.kind != .sum_type {
                    g.expr(node.right.expr)
                } else if elem_sym.info is ast.ArrayFixed
                    && node.right in [ast.CallExpr, ast.DumpExpr] {
                    fixed_info := elem_sym.info as ast.ArrayFixed
                    tmpvar := g.expr_with_var(node.right, elem_type, false)
                    g.fixed_array_var_init(tmpvar, false, fixed_info.elem_type, fixed_info.size)
                } else {
                    rhs_expr := g.expr_string_with_cast(node.right, right.typ, elem_type)
                    // Don't dereference when the expression was cast via a
                    // `_to_sumtype_` function, since that function already takes
                    // a pointer parameter and returns a value (not a pointer).
                    if needs_explicit_deref && !rhs_expr.trim_space().starts_with('*')
                        && !rhs_expr.contains('_to_sumtype_')
                        && !rhs_expr.contains('_to_Interface_') {
                        g.write('*')
                    }
                    g.write(rhs_expr)
                }
                if needs_clone {
                    g.write(')')
                }
            }
            if elem_is_array_var {
                g.write(')')
            } else {
                g.write(' }))')
            }
        }
    } else {
        g.gen_safe_shift_expr(node)
    }
}

fn (mut g Gen) need_tmp_var_in_array_call(node ast.Expr) bool {
    match node {
        ast.CallExpr {
            if node.left_type != 0 && g.table.sym(node.left_type).kind == .array
                && node.name in ['all', 'any', 'filter', 'map', 'count'] {
                return true
            }
        }
        ast.IndexExpr {
            return g.need_tmp_var_in_array_call(node.left)
        }
        ast.InfixExpr {
            return g.need_tmp_var_in_array_call(node.left)
                || g.need_tmp_var_in_array_call(node.right)
        }
        ast.ParExpr {
            return g.need_tmp_var_in_array_call(node.expr)
        }
        ast.PostfixExpr {
            return g.need_tmp_var_in_array_call(node.expr)
        }
        ast.PrefixExpr {
            return g.need_tmp_var_in_array_call(node.right)
        }
        ast.RangeExpr {
            return g.need_tmp_var_in_array_call(node.low) || g.need_tmp_var_in_array_call(node.high)
        }
        ast.SelectorExpr {
            return g.need_tmp_var_in_array_call(node.expr)
        }
        else {}
    }

    return false
}

fn (mut g Gen) expr_has_lambda_autofree_tmp_arg(expr ast.Expr) bool {
    match expr {
        ast.CallExpr {
            if expr.free_receiver {
                return true
            }
            if expr.args.any(it.typ == ast.string_type && it.is_tmp_autofree) {
                return true
            }
            if g.expr_has_lambda_autofree_tmp_arg(expr.left) {
                return true
            }
            for arg in expr.args {
                if g.expr_has_lambda_autofree_tmp_arg(arg.expr) {
                    return true
                }
            }
        }
        ast.CastExpr {
            return g.expr_has_lambda_autofree_tmp_arg(expr.expr)
        }
        ast.IfExpr {
            for branch in expr.branches {
                if g.expr_has_lambda_autofree_tmp_arg(branch.cond) {
                    return true
                }
                for stmt in branch.stmts {
                    if stmt is ast.ExprStmt && g.expr_has_lambda_autofree_tmp_arg(stmt.expr) {
                        return true
                    }
                }
            }
        }
        ast.IndexExpr {
            return g.expr_has_lambda_autofree_tmp_arg(expr.left)
                || g.expr_has_lambda_autofree_tmp_arg(expr.index)
        }
        ast.InfixExpr {
            return g.expr_has_lambda_autofree_tmp_arg(expr.left)
                || g.expr_has_lambda_autofree_tmp_arg(expr.right)
        }
        ast.ParExpr {
            return g.expr_has_lambda_autofree_tmp_arg(expr.expr)
        }
        ast.PostfixExpr {
            return g.expr_has_lambda_autofree_tmp_arg(expr.expr)
        }
        ast.PrefixExpr {
            return g.expr_has_lambda_autofree_tmp_arg(expr.right)
        }
        ast.SelectorExpr {
            return g.expr_has_lambda_autofree_tmp_arg(expr.expr)
        }
        else {}
    }

    return false
}

// infix_expr_and_or_op generates code for `&&` and `||`
fn (mut g Gen) infix_expr_and_or_op(node ast.InfixExpr) {
    rhs_has_lambda_autofree_tmp_arg := g.inside_lambda_autofree_tmp
        && g.expr_has_lambda_autofree_tmp_arg(node.right)
    if g.need_tmp_var_in_array_call(node.right) && g.inside_ternary == 0 {
        // `if a == 0 || arr.any(it.is_letter()) {...}`
        tmp := g.new_tmp_var()
        cur_line := g.go_before_last_stmt().trim_space()
        g.empty_line = true
        if g.infix_left_var_name.len > 0 {
            g.write('bool ${tmp} = ((${g.infix_left_var_name}) && ')
        } else {
            g.write('bool ${tmp} = (')
        }
        g.expr(node.left)
        g.writeln(');')
        g.set_current_pos_as_last_stmt_pos()
        g.write('${cur_line} ${tmp} ${node.op.str()} ')
        g.infix_left_var_name = if node.op == .and { tmp } else { '!${tmp}' }
        g.expr(node.right)
        g.infix_left_var_name = ''
    } else if (rhs_has_lambda_autofree_tmp_arg || g.need_tmp_var_in_expr(node.right))
        && g.inside_ternary == 0 {
        prev_inside_ternary := g.inside_ternary
        g.inside_ternary = 0
        tmp := g.new_tmp_var()
        cur_line := g.go_before_last_stmt().trim_space()
        g.empty_line = true
        if g.infix_left_var_name.len > 0 {
            g.write('bool ${tmp} = ((${g.infix_left_var_name}) && ')
        } else {
            g.write('bool ${tmp} = (')
        }
        g.expr(node.left)
        g.writeln(');')
        // Evaluate the right side with short-circuit: only evaluate if
        // left side is true (for &&) or false (for ||).
        // Use an if-block to prevent nested go_before_last_stmt() calls
        // from grabbing `cur_line` content during right-side evaluation.
        cond := if node.op == .and { tmp } else { '!${tmp}' }
        g.writeln('if (${cond}) {')
        g.indent++
        g.set_current_pos_as_last_stmt_pos()
        g.infix_left_var_name = ''
        lambda_autofree_tmp_arg_vars_start := g.lambda_autofree_tmp_arg_vars.len
        g.write('${tmp} = ')
        g.expr(node.right)
        g.writeln(';')
        if rhs_has_lambda_autofree_tmp_arg {
            g.write_lambda_autofree_tmp_arg_vars(lambda_autofree_tmp_arg_vars_start)
        }
        g.indent--
        g.writeln('}')
        g.set_current_pos_as_last_stmt_pos()
        g.write('${cur_line} ${tmp}')
        g.inside_ternary = prev_inside_ternary
    } else {
        g.gen_plain_infix_expr(node)
    }
}

fn (mut g Gen) gen_is_none_check(node ast.InfixExpr) {
    if node.left in [ast.Ident, ast.SelectorExpr, ast.IndexExpr, ast.CallExpr, ast.CTempVar, ast.CastExpr] {
        // When a sumtype variable has been comptime-smartcast to an option variant
        // (e.g. `$if t is ?string { if t == none { ... } }`), we need to access the
        // sumtype's variant field directly rather than using .data on the sumtype.
        if node.left is ast.Ident && node.left.obj is ast.Var
            && node.left.obj.ct_type_var == .smartcast {
            obj_sym := g.table.sym(g.unwrap_generic(node.left.obj.typ))
            if obj_sym.kind == .sum_type {
                ctyp := g.unwrap_generic(g.type_resolver.get_type(node.left))
                cur_variant_sym := g.table.sym(ctyp)
                variant_name := g.get_sumtype_variant_name(ctyp, cur_variant_sym)
                dot := if node.left.obj.orig_type.is_ptr() { '->' } else { '.' }
                // Sumtype stores option variants as pointers, so use -> to access state
                g.write('${node.left.name}${dot}_${variant_name}->state')
                g.write(' ${node.op.str()} 2') // none state
                return
            }
        }
        // For Ident nodes that have been unwrapped by a smartcast (e.g. from a
        // none-guard fallthrough), write the variable name directly to avoid
        // g.expr() generating the unwrapped data access instead of the option wrapper.
        if node.left is ast.Ident && node.left.obj is ast.Var && node.left.obj.is_unwrapped {
            name := c_name(node.left.name)
            if node.left.is_auto_heap() {
                g.write('(*${name})')
            } else {
                g.write(name)
            }
        } else {
            old_inside_opt_or_res := g.inside_opt_or_res
            g.inside_opt_or_res = true
            g.write('(')
            g.expr(node.left)
            g.write(')')
            g.inside_opt_or_res = old_inside_opt_or_res
        }
        dot_or_ptr := if !node.left_type.has_flag(.option_mut_param_t) { '.' } else { '->' }
        g.write('${dot_or_ptr}state')
    } else {
        stmt_str := g.go_before_last_stmt().trim_space()
        g.empty_line = true
        left_var := g.expr_with_opt(node.left, node.left_type, node.left_type)
        g.writeln(';')
        g.write2(stmt_str, ' ')
        dot_or_ptr := if !node.left_type.has_flag(.option_mut_param_t) { '.' } else { '->' }
        g.write('${left_var}${dot_or_ptr}state')
    }
    g.write(' ${node.op.str()} 2') // none state
}

struct VSafeArithmeticOp {
    typ ast.Type
    op  token.Kind
}

fn (mut g Gen) normalized_power_result_type(result_type ast.Type, left_type ast.Type, right_type ast.Type) ast.Type {
    mut typ :=
        g.unwrap_generic(g.recheck_concrete_type(result_type)).clear_flag(.shared_f).clear_flag(.atomic_f)
    if typ == 0 || typ == ast.void_type {
        typ = g.unwrap_generic(g.type_resolver.promote_type(g.unwrap_generic(left_type),
            g.unwrap_generic(right_type))).clear_flag(.shared_f).clear_flag(.atomic_f)
    }
    if typ == ast.int_literal_type {
        if left_type !in [ast.int_literal_type, ast.float_literal_type] {
            typ = g.unwrap_generic(left_type)
        } else if right_type !in [ast.int_literal_type, ast.float_literal_type] {
            typ = g.unwrap_generic(right_type)
        } else {
            typ = ast.int_type
        }
    } else if typ == ast.float_literal_type {
        if left_type !in [ast.int_literal_type, ast.float_literal_type] {
            typ = g.unwrap_generic(left_type)
        } else if right_type !in [ast.int_literal_type, ast.float_literal_type] {
            typ = g.unwrap_generic(right_type)
        } else {
            typ = ast.f64_type
        }
    }
    return typ.clear_flag(.shared_f).clear_flag(.atomic_f)
}

fn (mut g Gen) gen_power_expr_from_types(left ast.Expr, left_type ast.Type, right ast.Expr, right_type ast.Type, result_type ast.Type) {
    power_result_type := g.normalized_power_result_type(result_type, left_type, right_type)
    builtin_power_type := g.table.unalias_num_type(power_result_type)
    result_styp := g.styp(power_result_type)
    g.uses_power = true
    if builtin_power_type == ast.f32_type {
        g.write('(${result_styp})powf(')
        g.expr_with_cast(left, left_type, ast.f32_type)
        g.write(', ')
        g.expr_with_cast(right, right_type, ast.f32_type)
        g.write(')')
        return
    }
    if builtin_power_type.is_float() {
        g.write('(${result_styp})pow(')
        g.expr_with_cast(left, left_type, ast.f64_type)
        g.write(', ')
        g.expr_with_cast(right, right_type, ast.f64_type)
        g.write(')')
        return
    }
    if builtin_power_type.is_unsigned() {
        g.uses_power_u64 = true
        g.write('(${result_styp})__v_pow_u64(')
        g.expr_with_cast(left, left_type, ast.u64_type)
        g.write(', ')
        g.expr_with_cast(right, right_type, ast.i64_type)
        g.write(')')
        return
    }
    g.write('(${result_styp})__v_pow_i64(')
    g.expr_with_cast(left, left_type, ast.i64_type)
    g.write(', ')
    g.expr_with_cast(right, right_type, ast.i64_type)
    g.write(')')
}

// gen_plain_infix_expr generates basic code for infix expressions,
// without any overloading of any kind
// i.e. v`a + 1` => c`a + 1`
// It handles auto dereferencing of variables, as well as automatic casting
// (see Gen.expr_with_cast for more details)
fn (mut g Gen) gen_plain_infix_expr(node ast.InfixExpr) {
    mut resolved_left_type := g.resolved_expr_type(node.left, node.left_type)
    mut resolved_right_type := g.resolved_expr_type(node.right, node.right_type)
    // Don't override smartcasted concrete types with sumtype/interface from
    // resolved_expr_type (which doesn't check scope smartcasts).
    if resolved_left_type != 0 {
        resolved_sym := g.table.sym(resolved_left_type)
        left_sym := g.table.sym(node.left_type)
        is_sumtype_override := resolved_sym.kind in [.sum_type, .interface]
            && left_sym.kind !in [.sum_type, .interface]
        is_option_introduction := resolved_left_type.has_flag(.option)
            && !node.left_type.has_flag(.option)
        if is_sumtype_override || is_option_introduction {
            resolved_left_type = node.left_type
        }
    }
    if resolved_right_type != 0 {
        resolved_sym := g.table.sym(resolved_right_type)
        right_sym := g.table.sym(node.right_type)
        is_sumtype_override := resolved_sym.kind in [.sum_type, .interface]
            && right_sym.kind !in [.sum_type, .interface]
        is_option_introduction := resolved_right_type.has_flag(.option)
            && !node.right_type.has_flag(.option)
        if is_sumtype_override || is_option_introduction {
            resolved_right_type = node.right_type
        }
    }
    if node.op == .power {
        power_left_type := if resolved_left_type != 0 { resolved_left_type } else { node.left_type }
        power_right_type := if resolved_right_type != 0 {
            resolved_right_type
        } else {
            node.right_type
        }
        g.gen_power_expr_from_types(node.left, power_left_type, node.right, power_right_type,
            node.promoted_type)
        return
    }
    $if trace_ci_fixes ? {
        if g.file.path.contains('binary_search_tree.v') && node.right is ast.SelectorExpr {
            if node.right.expr is ast.Ident && node.right.expr.name == 'tree' {
                eprintln('plain infix op=${node.op} left=${g.table.type_to_str(resolved_left_type)} right=${g.table.type_to_str(resolved_right_type)} right_ptr=${resolved_right_type.is_ptr()} right_muls=${resolved_right_type.nr_muls()} node_left=${g.table.type_to_str(node.left_type)} node_right=${g.table.type_to_str(node.right_type)} expr=${node.right.expr.name}.${node.right.field_name}')
            }
        }
    }
    mut needs_cast := resolved_left_type.is_number() && resolved_right_type.is_number()
        && node.op in [.plus, .minus, .mul, .div, .mod] && !(g.pref.translated
        || g.file.is_translated)
    mut typ := node.promoted_type
    mut typ_str := g.styp(typ)
    if needs_cast {
        typ = if node.left_ct_expr {
            g.type_resolver.get_type_or_default(node.left, node.left_type)
        } else if node.left !in [ast.Ident, ast.CastExpr] && node.right_ct_expr {
            g.type_resolver.get_type_or_default(node.right, node.promoted_type)
        } else {
            node.promoted_type
        }
        // In generic contexts, the promoted type may be stale from a previous
        // instantiation. Recompute from the resolved operand types.
        if g.cur_fn != unsafe { nil } && g.cur_concrete_types.len > 0 {
            resolved_promoted := g.type_resolver.promote_type(g.unwrap_generic(resolved_left_type),
                g.unwrap_generic(resolved_right_type))
            if resolved_promoted != ast.void_type {
                typ = resolved_promoted
            }
        }
        typ_str = g.styp(typ)
        // Skip redundant cast when operands already have the same type,
        // but keep it for types smaller than int (u8, i8, u16, i16) because
        // C integer promotion rules would widen them to int.
        if resolved_left_type == resolved_right_type && resolved_left_type == typ {
            typ_kind := g.table.type_kind(typ)
            if typ_kind !in [.u8, .i8, .u16, .i16] {
                needs_cast = false
            }
        }
        if needs_cast {
            g.write('(${typ_str})(')
        }
    }
    // do not use promoted_type for overflow detect
    left_type := g.unwrap_generic(resolved_left_type)
    checkoverflow_op := g.do_int_overflow_checks && left_type.is_int()
    is_safe_add := checkoverflow_op && node.op == .plus
    is_safe_sub := checkoverflow_op && node.op == .minus
    is_safe_mul := checkoverflow_op && node.op == .mul
    is_integer_div_mod := g.table.final_sym(g.unwrap_generic(typ)).is_int()
    is_safe_div := node.op == .div && is_integer_div_mod
    is_safe_mod := node.op == .mod && is_integer_div_mod
    if resolved_left_type.is_ptr() && node.left.is_auto_deref_var()
        && !resolved_right_type.is_pointer() {
        g.write('*')
    } else if !g.inside_interface_deref && node.left is ast.Ident
        && g.table.is_interface_var(node.left.obj) {
        inside_interface_deref_old := g.inside_interface_deref
        g.inside_interface_deref = true
        defer(fn) {
            g.inside_interface_deref = inside_interface_deref_old
        }
    }
    is_ctemp_fixed_ret := node.op in [.eq, .ne] && node.left is ast.CTempVar
        && node.left.is_fixed_ret
    if is_ctemp_fixed_ret {
        if node.op == .eq {
            g.write('!')
        }
        g.write('memcmp(')
    }
    mut opstr := node.op.str()
    if is_safe_add || is_safe_sub || is_safe_mul || is_safe_div || is_safe_mod {
        overflow_styp := g.styp(get_overflow_fn_type(left_type))
        vsafe_fn_name := match true {
            is_safe_add { 'builtin__overflow__add_${overflow_styp}' }
            is_safe_sub { 'builtin__overflow__sub_${overflow_styp}' }
            is_safe_mul { 'builtin__overflow__mul_${overflow_styp}' }
            is_safe_div { 'VSAFE_DIV_${typ_str}' }
            is_safe_mod { 'VSAFE_MOD_${typ_str}' }
            else { '' }
        }

        g.write(vsafe_fn_name)
        g.write('(')
        if is_safe_div || is_safe_mod {
            g.vsafe_arithmetic_ops[vsafe_fn_name] = VSafeArithmeticOp{
                typ: typ
                op:  node.op
            }
        }
        opstr = ','
    }
    g.expr(node.left)
    if !is_ctemp_fixed_ret {
        g.write(' ')
        g.write(opstr)
        g.write(' ')
    } else {
        g.write(', ')
    }

    if is_ctemp_fixed_ret {
        g.write('(${g.styp(resolved_right_type)})')
    }
    if resolved_right_type.is_ptr() && node.right.is_auto_deref_var()
        && !resolved_left_type.is_pointer() {
        g.write('*')
        g.expr(node.right)
    } else {
        g.expr_with_cast(node.right, resolved_right_type, resolved_left_type)
    }
    if is_ctemp_fixed_ret {
        g.write(', sizeof(${g.styp(resolved_right_type)}))')
    }
    if is_safe_add || is_safe_sub || is_safe_mul || is_safe_div || is_safe_mod {
        g.write(')')
    }
    if needs_cast {
        g.write(')')
    }
}

fn (mut g Gen) op_arg(expr ast.Expr, expected ast.Type, got ast.Type) {
    mut needs_closing := false
    mut nr_muls := got.nr_muls()
    if expected.is_ptr() {
        if nr_muls > 0 {
            nr_muls--
        } else {
            if expr.is_lvalue() {
                g.write('&')
            } else {
                styp := g.styp(got.set_nr_muls(0))
                g.write('ADDR(${styp}, ')
                needs_closing = true
            }
        }
    }
    g.write('*'.repeat(nr_muls))
    g.expr(expr)
    if needs_closing {
        g.write(')')
    }
}

struct GenSafeIntegerCfg {
    op            token.Kind
    reverse       bool
    unsigned_type ast.Type
    unsigned_expr ast.Expr
    signed_type   ast.Type
    signed_expr   ast.Expr
}

// gen_safe_integer_infix_expr generates code for comparison of
// unsigned and signed integers
fn (mut g Gen) gen_safe_integer_infix_expr(cfg GenSafeIntegerCfg) {
    bitsize := if cfg.unsigned_type.idx() == ast.u32_type_idx
        && cfg.signed_type.idx() != ast.i64_type_idx {
        32
    } else {
        64
    }
    op_idx := int(cfg.op) - int(token.Kind.eq)
    op_str := if cfg.reverse { cmp_rev[op_idx] } else { cmp_str[op_idx] }
    g.write('_us${bitsize}_${op_str}(')
    g.expr(cfg.unsigned_expr)
    g.write(',')
    g.expr(cfg.signed_expr)
    g.write(')')
}